/*
 * Arduino LED Control Program with Array Implementation
 * 
 * Features:
 * - Controls 4 LEDs using arrays for efficient pin management
 * - Three push buttons with different LED effects:
 *   - SW0: Blink all LEDs (1s on/off)
 *   - SW1: Right-to-left chase (2s per LED)
 *   - SW2: Left-to-right chase (4s per LED)
 * - Uses internal pull-up resistors for button inputs
 * - Serial monitor feedback for debugging
 */

// ===== PIN CONFIGURATION USING ARRAYS =====
// LED pin array - change numbers to match your actual wiring
int LED[4] = {14, 15, 16, 17};  // GPIO pins for LEDs 1-4 respectively

// Button pin array with functional descriptions
int SW[3] = {11, 12, 13};      // GPIO pins for:
                                // SW0: Blink mode (index 0)
                                // SW1: Right-to-left chase (index 1)
                                // SW2: Left-to-right chase (index 2)

// ===== SETUP FUNCTION =====
void setup() {
  // Initialize serial communication at 115200 baud for debugging
  Serial.begin(115200);
  
  // Configure all LED pins as outputs using loop
  for(int i = 0; i < 4; i++) {
    pinMode(LED[i], OUTPUT);  // Set each LED pin as output
  }
  
  // Configure all button pins as inputs with internal pull-up resistors
  // Note: Buttons should be wired between these pins and GND
  for(int i = 0; i < 3; i++) {
    pinMode(SW[i], INPUT_PULLUP);  // Enable internal pull-up resistor
  }
  
  // Initialize all LEDs to OFF state
  for(int i = 0; i < 4; i++) {
    digitalWrite(LED[i], LOW);  // Ensure all LEDs start OFF
  }
  
  Serial.println("System initialized. Ready for button input...");
}

// ===== MAIN LOOP FUNCTION =====
void loop() {
  delay(10);  // Small delay to improve simulation performance
  
  // === Button0 (SW[0]) Handling - Blink Mode ===
  // Checks if button is pressed (LOW when pressed due to pull-up)
  while(digitalRead(SW[0]) == LOW) {
    Serial.println("LED IS BLINKING 1 SECOND DELAY, SWITCH0 IS PRESSED");
    
    // Turn all LEDs ON using array iteration
    for(int i = 0; i < 4; i++) {
      digitalWrite(LED[i], HIGH);  // Set current LED HIGH
    }
    delay(1000);  // Keep all LEDs ON for 1 second
    
    // Turn all LEDs OFF using array iteration
    for(int i = 0; i < 4; i++) {
      digitalWrite(LED[i], LOW);  // Set current LED LOW
    }
    delay(1000);  // Keep all LEDs OFF for 1 second
    
    // Effect continues while button is held down
  }
  
  // === Button1 (SW[1]) Handling - Right-to-Left Chase ===
  while(digitalRead(SW[1]) == LOW) {
    Serial.println("LED IS RUNNING RIGHT TO LEFT FOR 2 SECOND DELAY, SWITCH1 IS PRESSED");
    
    // Sequence: LED[0] → LED[1] → LED[2] → LED[3]
    for(int i = 0; i < 4; i++) {
      digitalWrite(LED[i], HIGH);  // Turn current LED ON
      delay(2000);                 // Keep ON for 2 seconds
      digitalWrite(LED[i], LOW);   // Turn current LED OFF
    }
  }

  // === Button2 (SW[2]) Handling - Left-to-Right Chase ===
  while(digitalRead(SW[2]) == LOW) {
    Serial.println("LED IS RUNNING LEFT TO RIGHT FOR 4 SECOND DELAY, SWITCH2 IS PRESSED");
    
    // Sequence: LED[3] → LED[2] → LED[1] → LED[0]
    for(int i = 3; i >= 0; i--) {
      digitalWrite(LED[i], HIGH);  // Turn current LED ON
      delay(4000);                 // Keep ON for 4 seconds
      digitalWrite(LED[i], LOW);    // Turn current LED OFF
    }
  }
  
  // === Default State (No Buttons Pressed) ===
  // Ensure all LEDs are OFF when no buttons are pressed
  for(int i = 0; i < 4; i++) {
    digitalWrite(LED[i], LOW);  // Turn each LED OFF
  }
  
  Serial.println("LED OFF, PRESS SWITCH TO TURN ON THE LED");
  delay(10);  // Small delay to improve simulation performance
}

/*
 * PROGRAM NOTES:
 * 
 * 1. HARDWARE CONNECTIONS:
 *    - LEDs should be connected with current-limiting resistors (220-1000 ohm)
 *    - Connect LED anodes to GPIO pins, cathodes to GND through resistors
 *    - Buttons should connect between GPIO pins and GND
 *    
 * 2. BEHAVIOR:
 *    - Button0 (SW[0]): Blinks all LEDs simultaneously (1s on/1s off)
 *    - Button1 (SW[1]): Chasing effect from first to last LED (2s each)
 *    - Button2 (SW[2]): Chasing effect from last to first LED (4s each)
 *    - Effects continue as long as buttons are held down
 *    
 * 3. TIMING:
 *    - All delays are in milliseconds
 *    - Main loop includes small delays to improve simulation performance
 *    
 * 4. SERIAL MONITOR:
 *    - Provides real-time feedback about system state
 *    - Baud rate must be set to 115200 to match the code
 */